Method for repairing radial tire, repaired radial tire, and patch rubber

A repaired radial tire comprising a tread portion, a pair of sidewall portions extending inwards in a tire radial direction from either edge of the tread portion, bead portions that extend respectively from the sidewall portions inwards in the tire radial direction, and a carcass having at least one radial carcass ply with a plurality of ply cords covered in ply rubber, the carcass ply extending toroidally across the bead portions, the sidewall portions, and the tread portion, wherein:

• at least one ply cord in the carcass ply is broken along with ply rubber at one of the sidewall portions;
• a patch rubber is attached from an inner side of the tire to a damaged portion of the carcass ply with the broken ply cord, the patch rubber including one or more reinforcement sheets, each with a plurality of reinforcing elements arranged in parallel and covered with rubber;
• the patch rubber is attached so that the reinforcing elements are parallel to a tire radial direction and so that inner edges of the reinforcing elements in the tire radial direction are positioned to at least partially have mutually different distances in a perpendicular direction from a tire circumferential line;
• the patch rubber has a generally trapezoidal shape;
• the patch rubber is attached so that a long side of the pair of parallel sides is located outwards in the tire radial direction, and a short side of the pair of parallel sides is located inwards in the tire radial direction;
• a plurality of the inner edges of the reinforcing elements in the tire radial direction are positioned on both oblique side edges of the trapezoid of the patch rubber, respectively, and
• in a plan view of the sidewall portion from inside the tire transparently showing the carcass ply closest to the inside of the tire, a region connecting four broken cord edges of two ply cords, among broken ply cords, most separated in a tire circumferential direction is defined as a damaged region, and an outermost side and an innermost side in the tire radial direction are respectively an upper side of length x and a lower side of length y;
• edges of the patch rubber positioned along an extension of the upper side are at a distance of (2 to 4)×(x/2) from a center P of the upper side;
• edges of the patch rubber positioned along an extension of the lower side are at a distance of (2 to 4)×(y/2) from a center Q of the lower side;
• and
• edges of the patch rubber positioned along a line PQ are at a distance of (2 to 4)×(z/2) from a center M of a line segment PQ of length z,
• wherein one end of all reinforcing elements in the patch rubber terminates at the long side of the pair of parallel sides,
• a hardness of the rubber covering the reinforcing elements is from 40 to 80,
• the rubber covering the reinforcing elements is the same as the ply rubber used in the carcass ply,
• the reinforcing elements comprise nylon cord with a cord diameter of between 0.4 to 1.5 mm,
• the tensile modulus of elasticity of the reinforcing elements is between 3.0 to 7.0 GPa, and
• the reinforcing elements are thinner than the ply cords.